1. Field of the Invention
This invention relates to a process for production of a gaseous mixture containing at least hydrogen (H2) and carbon monoxide (CO) starting from at least one hydrocarbon, in which a partial catalytic oxidation of at least one hydrocarbon is made in the presence of oxygen or a gas containing oxygen, to produce hydrogen and carbon monoxide.
2. Description of the Related Art
Hydrogen gas is widely used, particularly in the chemicals industry.
Thus, the annual global production of hydrogen is of the order of 50 billion m3, 95% of which is used in refining and the petrochemicals industry for the synthesis of methanol (MeOH) and the production of ammonia (NH3).
Therefore marketable hydrogen, in other words non-captive production, only represents a few percent of this global production.
It is becoming increasingly necessary to have production sources directly on the user site, considering increasing requirements for marketable hydrogen of the order of about +10% per year, and future needs felt in industry in general and particularly in chemicals industry, petrochemicals industry, metallurgy, electronics, fine chemicals industry, in the decentralized production of energy, clean and non-polluting transport using fuel cells and taking account of problems raised by the distribution infrastructure for hydrogen and particularly for its transport, storage and related safety problems.
Hydrogen is produced in large quantities mainly at refiners and major chemical companies using different known methods namely:                by reforming of hydrocarbons originating from oil fields (naphtha) or natural gas using steam. This is a highly endothermic reaction carried out at high pressure, for example of the order of 15 to 35 bars, at between 800° C. and 900° C. and with one or more catalysts. The burners are located outside the catalytic beds and the hydrocarbon/steam mixture is preheated due to heat exchangers that use hot combustion gases. This process can achieve H2/CO production ratios of between 3 and 4 depending on the steam flow.        by mixed reforming; this a auto-thermal process in which the thermal energy necessary for reforming with steam on a catalyst may for example be supplied by partial combustion of CH4 into CO2 and H2O. On the other hand, the H2/CO ratio is lower than it is for production by reforming with steam, in other words of the order of 2.2 to 2.5.        by partial oxidation of hydrocarbons. This process does not require a catalyst. Combustion takes place at between 1300° C. and 1400° C. with little or no steam. This process is exothermal but produces less hydrogen than the previous processes. Furthermore, the hydrogen production reaction must be maximised by conversion of CO in the presence of steam and on a catalyst, according to the following reaction (1):CO+H2O→CO2+H2  (1)        
Consequently for production of hydrogen alone, reforming with steam is the best process at the moment, particularly when it is associated with the gas to water conversion reaction and a PSA (Pressure Swing Adsorption) process for purification of the hydrogen thus produced.
The energy efficiency of this process is excellent, in other words up to 85% in large installations by making use of steam that is available in all cases.
Apart from specific production units, marketable hydrogen and therefore hydrogen in large quantities, is also obtained from other sources, namely:                recovery of hydrogen produced during dehydrogenisation operations in chemicals industry and refining, for example by catalytic reforming and cracking;        reuse of part of the hydrogen produced at captive producers when it is in excess. However, this source is shrinking due to the increasing needs of hydrogen firstly for removal of sulphide contents to satisfy environmental standards that are being adopted, and secondly for hydrogenisation treatment of increasingly heavy contents.        from production of coke in steelworks        electrolysis of sodium chloride (NaCl) in which hydrogen is produced at the same time as Cl2.        
There are also some small hydrogen production units based on the decomposition of molecules rich in hydrogen atoms, particularly thermal cracking of NH3, by catalytic reforming of CH3OH or by electrolytic dissociation of H2O.
However, hydrogen production from NH3 or CH3OH always requires delivery logistics for these liquid products.
Furthermore, ammonia (NH3) is a harmful pollutant for the environment (toxicity, odour, etc.) and regulations on this product are becoming increasingly severe.
Furthermore, the purchase price of these products fluctuates considerably which tends to reduce the global cost effectiveness of processes, particularly in the case of methanol.
Furthermore, production of hydrogen by electrolysis consumes a great deal of energy (of the order of 5 kWh/Nm3 of H2 produced) and this is not a good solution for production rates exceeding 50 Nm3/h in countries in which electricity is expensive.
Therefore these various hydrogen production processes have many disadvantages, and no existing production process can be considered to be fully satisfactory from the industrial point of view.
The problem that arises is then to be able to propose a hydrogen production process that is better than known processes, in other words with easier maintenance or implementation, lower investment cost, or that uses natural gas or LPG for the production of hydrogen and that requires few utilities (water, steam, etc.).